Exhaust heater



E. H. CARRUTHERS Aug. 15, 1939.

EXHAUST HEATER Filed May 14, 1936 3 Sheets-Sheet 1 INVENTOR if ATTORNEYAug. 15, 1939.

E. H. CARRUTHERS EXHAUST HEATER Filed May 14, 1936 3 Sheets-Sheet 3ATTORN Y Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE EXHAUSTHEATER Application May 14, 1936, Serial No. 79,627

' 11 Claims.

In the reclaiming of spent lubricating oils, transformer oils, and thelike, it is customary to subject these oils to a treatment comprising acentrifuging operation which has for its purpose the separation of theoil from associated contaminating materials, such as water, carbon, orthe like, the centrifuging process throwing the contaminants into anouter zone of the centrifuge, from which they may be discharged, whilethe oil, being lighter, remains in the inner compartment or section ofthe centrifuge, so that the oil and the contaminants are separatelydischarged from the centrifuge.

In order to treat the oil in this manner effectively, it; is necessarythat its viscosity be sulficiently low so that its fluidity will permitthe ready separation of the oil and contaminants. However, in view ofthe fact that many lubricating oils, transformer oils, Dieselengine fueloils, and the like, are of normally relatively high viscosity, itbecomes necessary to preheat them to impart thereto the necessary degreeof fluidity for effective centrifugal separation; and the oils must beat a suitable temperature in the centrifuge in order for the treatmentto proceed in a satisfactory manner.

The present invention has for its object, therefore, the provision of aheater for use in heating lubricating oils for Diesel engines and thelike preparatory to centrifugal purification of these oils, in whichheater there is utilized the heat from the exhaust of the engines, andin which the drawbacks and disadvantages both as to electric heaters andheaters using sources of heat other than electricity, are obviated.

A further object of the invention is to provide a heater of this type,utilizing the waste gas from a Diesel engine as the heating medium,which will prevent overheating of the oil, which will control in aneffective and efiicient manner the heat interchange between the gasesand the oil being treated, which will be easily accessible for cleaning,and which will be composed of a relatively few simple parts which have aminimum likelihood for getting out of order, but which if they do can bereplaced with ease.

Other objects of the invention will in part be obvious and will in partappear hereinafter. The invention accordingly comprises the features,properties, and the relation of elements which will be exemplified inthe construction hereinafter described and the scope of the applicationof which will be indicated in the claims.

For a complete understanding of the present invention, reference may behad to the accompanying drawings, wherein V Fig. 1 is a diagrammaticassembly, partially in section and partially in elevation of theapparatus of the present invention as used in connection with, acentrifugal purifier.

Fig. 2 is an exterior end view of the present improved unit, the viewbeing taken exteriorly of the casing thereof and illustrating one way ofmounting the heater unit in position for service.

Fig. 3 is a sectional elevation of the improved heater unit embracingthe features of the present invention, the view showing the gas-controlvalve in closed position and the circulation of the heating gas with thevalve in. the said closed position, the View being taken on the line3--3 of Figure 2.

Fig. 4 is a sectional elevation of the heater unit taken atapproximately right angles to Fig. 3, the gas manifold being shown insection and the gascontrol valve in open position, the casing of theheat exchange element being partially broken away to show thecirculation of the heating gases when they are flowing in heat-exchangerelation with the oil being treated.

Fig. 5 is a view of the outside of the housing for the gas-valve controlmechanism.

Fig. 6 is a sectional elevation of the valve control mechanism, the Viewbeing taken on the line 6-6 of Fig. 5, the thermostat housing beingpartially broken away.

Fig. '7 is also a sectional elevation of the valvecontrol mechanism, theview being taken on the line 1-1 of Fig. 5, orFig. 6 the solenoidhousing being shownin elevation.

Fig. 8 is a sectional view through the heat exchanger taken on the line88 of Fig. 3, looking in the direction of the arrows.

Fig. 9 is a sectional plan view of the heater unit shown in Figs. 3 and4, the view being taken on the line 99 of Fig. 3, looking in thedirection of the arrows.

Referring more particularly to the drawings, it will be seen from Fig.1, that the improved mechanism indicated at A may be interconnected witha centrifugal purifier B, so that the oil being treated in the purifiermay be circulated through the heater for reducing the viscosity of theoil sufiiciently for enabling it to be purified in the centrifugalpurifier B.

The centrifugal purifier B is of a usual construction, which need not bedescribed, and it has associated with it a gear pump l0 of any suitabletype for handling the oil to be treated, this oil being spentlubricating oil, fuel oil, or the like, as previously mentioned above.It enters 7 controlled by a relief valve I8 comprising a tion side ofthe pump I0, through a strainer I4 the system through the intake pipeI2, which receives the oil from any supply thereof,. which may be astorage tank, the oil flowing through the pipe I2 being cold and ofrelatively high viscosity.

The intake pipe I2 communicates with the sucpositioned in a housing I6.As indicated by arrow I8 the oil passes through the outlet 20 of thehousing I6, this outlet registering with intake 22 of the pump I0.Flange 24 affords connecting means between the strainer housing I6 andpump housing 26 of the pump I0. 7

The pressure side of the pump I communicates through passage 28 withpipe 30, the oil being forced therethrough under-pressure of the pump,as indicated by the arrow 32. T

The pipe 30 enters housing 84 of the valve control mechanism, whichmechanism will be described in detail hereinafter, the pipe 30communicating with the intake port 36 of the housing .34. A' pipe" 38connects the housing 34 with the heat exchanger 40, wherein the oil iscaused 60' v r the pressure on the circulating oil.

As will be seen from Fig. 1, the arrows 44 and 45 indicate the directionof fiow of the oil into the heat exchanger 40, the end 48 of the h eatexchanger receiving the intakepipe 50. As the oil" spirals through theheat exchanger 40 in the direction indicated by the arrows 52, itbecomes heated and lowered in viscosity, and it flows from the heatexchanger through an outlet passage 54- into the housing 34 of the valvecontrol mechanism, thence out, as indicated by arrows 56 and 58, by wayof outlet 80 into a pipe line 62 which leads to the oentrifugalpurifierB.

The pipe line 62 branches, as indicated at 64, one branch 66communicating with the strainer housing I6, the other branch 68 leadingto the centrifugal purifier B.

A valve I0 is positioned in the branch 68, for controlling the directionof fiow of the oil through the respective branches'66'and 68; closing ofthe valve I8 causing the oil to be by-passed through the branch 66, theninto thestrainer I4, as indicated by the arrow I2; On the other hand,when the valve I0 is opened, the heated oil may pass into the branch 68,as shown by arrow 1'4 and flow into the centrifugal separator B by wayof pipe I6.

It will be seen also that the branch 66 is sprin -R essed ball valvemember 80' which is normally maintained seated over the outlet of V thebranch 68 by pressure of a spring 82, which spring is compressedbetween" the valve member 80 and the spring adjusting screw 84 which isthreadedly mounted in the valve housing 86. The compression of thespring 82' is adjusted by manual adjustment of the screw 84, a handle 88being provided for this purpose. A gage 90 indicates The heated 1 oil.may therefore be recycled through'the heater or through the purifier B,

selectively. I

usual type, the construction of the heatexchanger and valve controlmechanism may now be described. f

The casing 40 (Fig. 3) is a generally cylindrical housing provided witha closed end 48 which receives the pipe 50 as has been described above.The other 'endof thecasing 40 is provided with a flange 92 and an outlet94 which communicates with thehousing 34' of the Valve controlmechanismto be described hereinafter.

The pump and associated parts being of the The casing 40 receives ametallic casting 96, which is preferably made of aluminum because of itslightness and high heat conductivity, al-.

though it may be made of any other desired metal; This casting 96 is inthe general form of a hollow cylinder having a closed end 98. Theinterior of this casting 96 is provided with longitudinally extendingcorrugations or fins I00, which are par-1 tubular casing 40. I

" As the oil flows in a shallow or thin stream.

through the spiral groove I02, it becomes heated by heat conductedthrough the'casting 96 from 1 hot combustion gases passing through theinterior of the casting 96. These gases are brought into heat exchangerelation with the oilby way of agas manifold I06, which comprises acylindric'al casting I68 having a flange H9 which is bolted to theflange I04 of the'heat exchanger 96 and the flange 92 of the casing 40by suitable bolts II2. On the outer end ofthe cylinder I08 is bolted amanifold casting II4 which forms a cover .for the cylinder-I08, whichincludes any elbow-shaped intake deflector II6, which intake deflectoris provided with a flange I I8 for bolting to a boss I20 of thecylindrical casting I08, by bolts I54. a

' Now it will be seen from Figs. 2, 3 and 4, that the cylindricalcasting I88 is provided with several, preferably four, openings or portsprovided with bosses similar to the boss I20, and studs to Any two ofthese openings may be used as the inlet and outlet, respectively,

' of the gas flow, the manifold casting II4 being takefianged fittings.

positioned so that itheelbow deflector II6 aligns with any one of theseopenings, to which opening the gas inlet pipe I22 is connected by meansof bolts I24 passing through the flange I25 of the pipe I22 and into theboss I20. V

In a similar mannen the gas outlet pipe I28 is bolted by means of boltsI29 to another one of the openings or ports inthe casting I08, the boltsI29 passing into a boss I3I at this other opening.

Either of the other bosses may be used for bolting this manifold andthen out by Way of the gas outlet if pipe I28, the gases simplyenteringthe manifold from" the intake pipe- I22 .by way. of the elbow deflectorH8, passing through the manifold'and out through the outlet pipe I28.

' In Fig. 4, the arrows show the circulation of the gases through theheat exchanger for heating the oil when the gas valve I26 is in openposition. This gas valve I26 is an open ended tube provided withexterior guides or spacers I 36, and interiorly With'an annular collarI37 to serve as an abutment for valve operating means to be de' scribedhereinafter; V

The valve I26 is of somewhat smaller diameter. than the inner diameterof the heat exchanger casting 96, so that the valve I26 can slide intoand out of the heat exchanger casting 96, the movement of the valve I26being guided by the spacers I36 which slide in the depressions I38between the fins I00 on the inside of the heat exchanger casting 96.

One end of the tubular valve I26 is provided with an annular flange I40which is secured to the valve I26 in any suitable manner, this flangeI40 being of suflicient diameter to cover the annular space I42 betweenthe tubular valve I26 and the inside of the heat exchanger casting 96,when the valve I26 is closed. i

The flange I40 is provided with an opening I44 through which extends avalve stem I46 to which are secured radially extending arms I48 near theend of the stem which is within the tubular valve I26. These arms I48are adapted to engage the underside of the flange I40 as the valve stemis moved outwardly relative to the valve I26 for shifting the valve toopen position, and as the valve stem is moved inwardly relative to thevalve I26, the arms I48 abut against the collar I31 for shifting thevalve I26 to closed position.

When the valve I26 is closed, the flange I40 engages the end surface ofthe heat exchange casting 96, thus blocking flow of gases through theheat exchanger, while when the valve I26 is in open position, it hasshifted relatively to the casting 96 so that the flange I40 has movedaway from the end surface of the casting 96 until the flange I40 abutsagainst the inner end or port 91, of the deflector II6, thus registeringwith the deflector and passing the gases into the valve I26, as theby-pass passage for the gases through the manifold is now out off.

Thus, when the valve I26 is open, the hot gases pass through thistubular valve, through the opening between it and the end 98 of thecasting 96, and thence through the space I42 between the valve I26 andthe heat exchanger casting 96, the gases giving up their heat to thecolder oil passing through the groove I02 by conduction of the heatthrough the casting 96. V

In order to facilitate and to guide the flow of gases around the end ofthe tubular valve I26 and between the end 98 of the casing 96, thelatter is provided with a projecting guide or deflector I50 which has aconvex surface for deflecting the gases around the end of the valve tubeI26.

It will be seen that the valve stem I46 extends through the manifoldcasting II4, which casting is provided, of course, with a suitableopening for the passage of the valve stem I46.

This valve stem I46 is provided intermediate its ends with a cup-shapedretaining member I56 which is secured to the stem I46 and receives acoiled spring I58, which is compressed between the retaining cup I56 andthe top I60 of the spring housingI62. This spring housing I62 isprovided with a flange I64 which may be flush with the flange N8 of themanifold casting II4, which may be provided ,with an annular groove orrecess I66 in which the flange I64 cf the spring housing may be receivedand sealed to form a gas-tight seal I52, which may be retained by meansof bolts I65. The closed end I68 of the spring housing I62 forms a guidefor the valve stem I46, and the cover I60 is provided with a boss I10which acts as a retainer and guide for the spring I58. .The springhousing I62 is provided with a flange I12 to which the cover I60 isbolted by means of bolts I14. The boss I10 also serves as a guide forthe valve stem I46, which valve stem is enclosed in a sleeve I15 whichmay be renewed readily when worn, this sleeve and a valve stem extendinginto the opening I16 provided in the cover I60 for this purpose. The endof the valve stem I46 is provided with a, nut I18 which acts as aretainer for the sleeve I15.

The spring I58 normally urges the arms I48 towards the collar I31 in thevalve I26, to tend to hold the flange I40 against the end of the casting96. v

The operating mechanism for the valve I26 includes a lever I whichextends through the spring housing I62. This lever I80 is .fulcrumed ona lug I82 upstanding from the flange I64 of the spring housing, and isconnected to the spring retaining cup I56 by a yoke I84 and pins I86which connect the yoke to the cup I56. The fulcrum lug I82 is adjacentto one end of the lever I80, the other end of the lever being providedwith an abutment I88 which engages with the end piece I90 of the pistonrod I92 ofga valve actuating piston I 94 (see Fig. 6), so that as the athus allowing hot gases to flow through the heat exchanger to heat theoil passing alongthe spiral groove or thread I02.

Conversely, when the piston rod I92 falls, as viewed in Fig. 3, thepressure on the spring I58 is relieved and the spring moves the valvestem I46 so as to disengage the arms I48 from the flange I40 andengaging the arms with the collar I31, thus allowing the valve I26 toshift into closed position to out 0115 the flow of the gases through theheat exchanger.

It will be seen from Fig. 6 that the end piece I90 of the piston rod I92is in effect, a sleeve which is fitted over the end of the rod I92, thepiece I90 forming an abutment member for engaging the abutment I88 onthe lever I80. The abutment I90 is hollow and is internally threaded asindicated at I96 for intermeshing with threads I98 on the piston rodI92, thereby enabling the stem for efiecting any desired adjustmentofthe 4 amount of movement of the lever I80. A look nut 200 holds theabutment I90 in the desired adjusted position. v

The piston I94 is essentially a fluid actuated piston which is securedto the rod I92 by a nut 202 and which operates in cylinder 204 in thehousing 34.

The intake 208 of the housing 34 is bossed, as indicated at 2I0 forconnecting with a corresponding boss 2I2 (Fig. 3) of the fluid outlet 54of the heat exchanger. The housing 34 and the cylinder 204 are closed bya flanged cover 2I4, which is bolted to the housing 34 by bolts 2I6.

The cover 2I4 forms a guide for the rod I92'and closes the recess 2I8and forms :an additional guide forthe rod I92.

Thepiston' I94 is a fluid operated piston the action of which iscontrolled by the temperature of the oil flowing through the system, theflow of which oil is controlled in turn by a piston valve 228 operatingin a cylinder 238 in a housing 232. ,'The cylinder 230is incommunication with the cylinder 264 bya passage 234 which extends from aport 235 in the upper part of the cylinder 238 to the port 231 in thelower part of the cylinder 204 so as to be beneath the piston I94. The

piston valve 228 is provided with upper and lower flanges 236 and 238,respectively, which are interconnected by the valve body, and isprovided with an internal channel 242, extending longitudinally throughthe valve and communicating with a space 244 in which is positioned aspring 248 which. presses against the valve 228. Between the flanges 236and 238 of the valve 228 there is an annular space 248 with whichconnects the oil line 38 from the discharge side of the pump I0 (Fig. 1)and an outlet 250 from the space 248 connects with the pipe 38 leadingto theintake port 252 of the heat exchanger.

.The spring 246 is seated between the flange 254. and the valve 228,bearing upon the valve flange 236'to tend to maintain the valve 228pushed towards the port'255 in the end of the cylinder 238. A'sniallopening 256 in the valve 228 connects the valve channel 242 with thespace 258 between the valve flange 238 and the end closure 268 of thecylinder. 288, which closure contains the port 255. The purpose of thisconstruction will become apparent hereinafter.

Now, referring back to the cylinder 284 in V way of a port 268 whichpasses through the flange 254. The hot' oil line 62 connects the space248 with the centrifugalpurifler B (Fig. 1) and with the intake side ofthe pump .IO, whereby the heated oil maybe circulatedthrough'thepurifier, or recycled through the system as'may be desired.

The thermostat 266 operates a switchindicated at 218 enclosed in'ahousing 212, which switch, :as is shown in Fig. 5,. is in electricalcircuit through conductors 214, 216, 218,. 288'-and 282 with asolenoidvalve 284 (Fig. '7), the solenoid .of which (not shown) is enclosedin'housing 266. Operating power is taken from a power'line 288 (Fig. 5)to the respective sides of which are connected the conductors 216 and278. A manual switch 290 may be included in the circuit, it

'being understood that thisswitch is closed while the apparatus is inoperation.

The solenoid valve 284 operates in a space 292' which is in a housing294 and which communicates with the space 248 between the valve flanges236 and238, by a connection 294'. ;The solenoid 1 valve 284 isarranged'to open and close a port 296 which is connected'by a pipe 298'withthe port'255 under the piston valve 248. The port 296 extendsthrougha flange 308 which forms a seat for the valve 284. s In operatingthe..present system, the: oil being treated, such 'as lubricating oil,.fuel oil, .or 7 other high viscosity 0i1,.is fed'into the systemthrough the supply pipe I2 and through the pump I9 by way of the filterscreen I4. The pump-I8 forces the oil through the pipe '38 into thespace 248 between the flanges 236 and'238 of the piston valve 228 whichis yet in closed position as shown in Fig. '7 through action of thespring 246, and flowing around the valve 228 it fills the pipeconnection 294 and the space 292 around the solenoid valve 284, which isstill seated or closed, as indicated in Fig. 7. Therefore, the oilcannot reach the by-pass pipe 298, but it will flow out from the space248 by way of port 258 into the pipe 38 which connects with the intakeport1252 in the closed end 48 of the casing 46 of the heat exchanger.

The ones it passes into the heat exchanger follows thespiral I82 throughthe exchanger casing 48 until it comes to the outlet 54, passing 1therethrough into the intake 288 of the valve piston housing 286 (Fig.6), and passes around the thermostat 266, thence into space 244, andthence through the pipe 62 back through the pump I0, it being understoodthat the valve 18 is closed while the oil is recycling. This circulationof the oil is maintained continuously, as long' as the pump I8 isoperating.

At this stage of operation, since the by-pass pipe 298 is empty and thevalve 228 is'in position against the end piece 268 of the cylinder 238,see Fig. '7, the flange 236 of the valve will closecommuni'cationbetween the chamber 248 between the valve'flan'ges 2 36and 238 and the port 235 (Fig. 6), thereby closing communication betweenthe chamber 248 and the cylinder 204 in front of the valve piston I94.Therefore, the cylinder 284 is empty of oil, and'valve piston I94 willbe at its closest position to the cylinder head 283 of the cylinder 204,the piston I94 being held in that position by the pressure of spring I58acting on the retainer cup I56 (Fig.3), which pressure 7 is transmittedto the piston'rod I92 through the lever I88 by way of itsyokeconnectionI84, with the cup I56. The spring I58 also holds the arms I48 on thevalve'stem I46-out of engagement with the flange 'I48:of the gas valveI2 6, the arms I48 being pressed against the collar I37, the valve I26thereby being held closed as in Fig. 3 sothat hot gases; such as hotcombustion gases entering the manifold I86 through the intake I22 passout immediately through the outlet'l28 without being enabled to passthrough the valve I26. There fore, the oil flowing through the spiralgroove I82'cannot be heated, but as has been said before;

this oil althoughlcold is continuously circulated as long as the pump;I8'is operating.

Now, let the manual switch 288, Fig. 5, be

closed. The thermostat 266, which is set to operate at a predetermineddesired elevated temperature, say 180 F., is still immersed in cold oil.

The solenoid valve circuit will be energized, opening the solenoidvalve'284, and allowing oil from" the space 248 to flow into the by-passpipe .298.

.This' flow is greater than the counter-flow ofoil through the smallopening 256 in the piston valve 238, so that this piston 'valve 238 willbe lifted againstthe pressure of the spring 248, thus opening thepassage 234, as shown in' 'Fig..6,;a nd admitting oil in front .of thevalve pistonI94, mov

ing it and the rodI92 against the lever I88 (Fig.

3) and, overcoming the pressure of the spring I58, causes the armsl48 toengage the flange I49 of the valve I26,-opening' the latter as shown inFig. 4 and allowing the hot gases to pass therethrough I Thus, withregard to the heat exchanger itself,

and around in the space I42 between the valve I 26 and the casting 96,thus heating the oil by heat conduction through the casting 96.

The oil thus heated passes around the thermostat 266 until it is broughtto required temperature, when the thermostat 266 operates to break thecircuit through the solenoid valve, which immediately closes, cuttingoff oil flow into the pipe 298. The release of oil pressure in pipe 298relieves the pressure behind the piston valve 228, allowing the spring246 to move the valve, the oil in the portion 258 of the piston valvecylinder be-' ing displaced through the opening 256 in the piston valveby movement of the valve.

When the piston valve 228 thus moves, its flange 236 passes the port 235and puts the passage 234 in connection with the discharge from the heatexchanger, thus destroying the pressure difference across the valvepiston I94, thus enabling the spring I58 to act on the lever I to pushthe piston I94 towards the head 203 of the cylinder 204, allowing thegas valve I26 to return to the closed position of Fig. 3. The flow ofgas, as indicated by the arrows of Fig. 2, by-passes the heat exchangerand flows through the gas manifold I06 only. The oil flow continues thesame.

The thermostat 266 may be of any standard construction such as a liquidthermostat containing a liquid which boils in the thermostat at adefinite temperature, so that when the thermostat reaches thattemperature, the liquid vaporizes and breaks the circuit through thesolenoid valve 284. When the oil cools, the volatilized liquid in thethermostat recondenses, so that the thermostat becomes automaticallyoperative. This is a well-known type of thermostatic switch, andrequires no further description.

It may be pointed out at this point that in prior heaters of thisgeneral type using electric heat, there is a tendency for oil tocarbonize due to the high temperatures of the surfaces of the heaterelements. These high temperatures not only carbonize the oil but bakethe carbon on the heater elements, reducing the heat transfer andefiiciency of the heater. Also, where moving oil is being heated, thereare likely to be film effects due to the presence of a stationary filmof oil between the moving oil and the heating elements, which film ofoil acts as a high heat insulator, as well as tending to becomecarbonized by overheating. a

In the present construction, however, there are of course no electricheating elements, and the spiral groove I92 minimizes film effects byproducing a rapid and turbulent fiow of oil around the heat exchangecylinder 96, which prevents the formation of stationary film by breakingup such film, thereby minimizing possibility of local overheating of theoil.

Furthermore, the present construction is characterized by the fact thatthe parts may be readily dissembled for convenient access to the variousparts for purposes of cleaning, and the surfaces of the heat exchangerthat are exposed to the oil and gases are all arranged for easycleaning. Thus by removing bolts H2, the manifold casing I06 may beremoved, and access had to all parts of the heat exchanger; and in thisconnection it may be noted that the inside fins I00 of the heat exchangecasting 96 are parallel to the axis of the casting to allow easycleaning.

With reference to the improved structure herein described, it will beseen that it possesses definite advantages with respect to the variousparts of the. construction,

itwill be seen that it is made up of two parts with only one oil-tightjoint to be maintained; that the continuous helical oil passage formedby the thread-like groove I02 on the outside of the exchanger casting 96insures a flow of fluid over the entire surface, eliminating dead areaswhere carbon or other solid matter which may be present in the oil mightcollect; that removal of the exchanger shell 40 exposes the entire oilpassage surface for quick and easy cleaning; that the design of theexchanger allows the ratio of gas surface area to oil surface area to bemade most suitable for results desired; that the large area of fiuidcontact with the assured rapid movement of the fiuid preventsoverheating of the oil film on the exchanger threads with consequentelimination of carbon formation when oils are being heated.

With regard to the manifold, the manifold casting I08 is provided with anumber of ports and bosses, any of which can be used either for inlet oroutlet piping or for mounting to the support plate. This allows thepiping to be arranged in any manner meeting the requirements of anyspecific plant arrangement. When the manifold cover plate H4 iswithdrawn, the deflecting elbow II6, valve stem I46, and valve I26 arewithdrawn with it, thus leaving a clear opening into the inner surfacesof the heat exchanger casting 96. Thus the exchanger shell 40 alone, orboth shell and exchanger body, may be detached from the manifold withoutdisturbing the piping with exception of pipe 38, or the mounting of theheater.

With regard to the gas valve I26, it will be seen that it has no slidingseats that might be fouled by carbon or soot deposits. With the valve inthe nonheating position, the flow of gas through the piping to and fromthe heater is not stopped, this keeping the pipes and manifold hot allthe time the heater is in operation, whereas stopping the flow of gasintermittently would cause cooling with consequent formation ofcorrosive liquids in the gas passages.

With regard to the valve operating mechanism, it will be seen that it issimple and positive in its action, and closely responsive in itsoperation to temperature changes of predetermined amounts in the oil;and also the valve operating mechanism incorporates automatic safetyfeatures in allowing the gas valve to return to nonheating position bythe automatic thermal switch control, or by breaking of the electriccircuit to the thermostatic switch, or by failure of oil circulationthrough the exchanger.

It will be seen that the entire discharge from the heater may bereturned to the suction side of the pump I0 through the relief valve 80,or part of it may be delivered to the purifier B by opening the valveI0. When the valve 10 is opened, and the hot oil fiows into the purifierB, an equal amount of oil enters the system through the supply pipe I2for treatment, so that a quantity of oil equal to the whole pumpcapacity is continually circulated through the heater while the pump isrunning.

It will be understood, of course, that all joints and connectionsbetween the various parts of the construction are rendered gas-tight andfluid tight by the use of suitable gaskets and/or packing, as will bewell understood.

While the specific heating medium described herein is hot exhaust gasesfrom the engine, it will be understood that other fluid heatingmediunrs;may be used; such as for example, *hotiair I or steam; if theconditions of operation render theme of such ,heating-materialsrto-bedesirable. It will be understood,' of course, that the invention 'is notlimited necessarily; to the specific details of the construction asherein illustrated and described, but that various 'modifica'tions inthe-construction-may'be made without departing fromthe scope of theinvention, it being intended that all matter containedin the abovedescription'or shown in the accompanying drawings are to be interpretedgas being only illustrative and not in a limitingjsense.

lt'isalsoto be understood that the following claims are intended-tocover all of the generic and specific 'features' herein described, andall statements of the scope of the invention, which, as a matter'oflanguage, might be said to fall between; and that it is intendejd'anddesired to embrace Wlfhllf the scopeof the invention such modificationsand changes as may be'necessary toi adapt it to varying: conditions and.uses.

What is claimed is:

1. 'A heater-for fluids comprising the combination with means-forcirculating the fluid; of a heat exchanger through which the fluid flowscomprising shiftable means for controllingadmission of hot gases intoheat exchange relation with fluid" passing through the heat exchanger, agas manifold adapted to admit hot gases to the heat exchanger when the*saidshiftabl'e'means are in positon for admitting gases'to'th'e heatexchanger and to by-pass' the gases when the said means are in positionto block admission of gases to the heat exchanger, instrumentalitiesforroperating the-said means, including pressure actuated devices forshifting'the' said means, temperature responsive instrumentalitiesoperable responsively to temperature variations in the fluid ofpredetermined amounts, and a control valve 'for controlling the saidpressure actuated devices" responsive to actuation of the tempera.- tureresponsive ins'trumentalities 'for actuating the said shiftable means inaccordance with the temperature variations in the fluid.

2. Aheater for fluids comprising the combination 'withmeans forcirculating thetfluidfof a heat exchanger through which the fluid flowscomprising a casing-,omeans inthe casing for imparting a tortuous pathof circulation for the fluid flowing through" the exchanger, a.shiftable bafile valve disposed interiorly of the said means forcontrolling admission of hot gases into the said'means'and in heatexchange relation with fluid passing throughthe'heat exchanger when thesaid bafile valve is in position for admitting gases to the heatexchanger and to by -pass the gases when thesaid valve is in 'positionto block admission of gases into the said means, instrumentalities'including pressure operated devices for "shifting'the said bafilevalve,'valve means for regulating" the pressuref'operatingsaid devices,

and thermostatic 'means for. controlling said valve' means in responseto temperaturechanges of predetermined amounts in said fluidIi 3. Aheating "apparatus for fluids comprising the combination with a casingof heat exchange inst'rumentali'ties. within the casing including ahollow cylindrical castin'g'defining a fluidv passage between thecasting and the casing, a. tubularbaflle valve within the casting forcontrolling admission of hot gases intothe said casting'to admit and toprevent, respectively, flow of gases according todiflferences inposition of the bafile valve,; the said valve defining a gas"circulation space between the "casting and the valvefaninternal'abutment in the valve, means adapted to admit'gases to theinterior of the baffle valve when the valve is in open'position and toby pass the gases when the valve is in closed position,instrumentalitiesfor shifting the said valve including a valve stem provided with armsdisposed in the valve for engaging the'valveto shift the same relativeto the casting, ,a lever connected to the valve stem and a spring urgingthe stem and arms thereon into disengagement with the valve and intoengagement with the abutment therein, the said lever being pivoted forsubstantially straight-line movement, and interacting valve andthermostatic control mechanism for operating the said instrumentalitiesresponsively to temperature changes of predetermined amounts in thefluid circulating through the apparatus.

4. A heating apparatus for fluids'comprising,

in combination, a heat exchanger through which fluid to be heated mayflow, means for passing a heating medium into the heat exchanger in heatexchange relation with a fluid passing through the heat exchanger,instrumentalites for controlling the passage of the heating medium intothe heat exchanger, and mechanism for operating the instrumentalities,the 7 said mechanism comprising a thermostatic switch operableresponsively to temperature changes of predetermined amounts in thefluid circulating through the apparatus, a solenoid control valveoperated by the thermostatic switch, and valve and piston mechanismoperated by fluid pressure transmitted by the said control valve foroperating the said instrumentalites for controlling the heating mediumfor the fluid.

5. A heating apparatus for fluids comprising, in combination, a heatexchanger through which fluid to be heated may pass, instrumentalitiesfor introducing heating gases into the heat exchanger, the saidinstrumentalities comprising a cylindrical casting'having a plurality ofports pr vided with connecting bosses, an inlet pipe connected to one ofthe ports, an outlet pipef conthe intake port and pipe and adapted todirect heating: gases intothe heat exchanger, a lay-pass for thegasesthrough the manifold, and means for'directing'fl'ow of gases from theintake deflector into theheat exchanger and through the by-pass;alternatively, and means for connecting the heat exchanger'to thegas-'introducinginstrumentalities. l

6. A heating apparatus for fluids comprising, in combination, a heatexchanger through which fluid to be heated is adapted to flow, the saidheat exchanger having an open end and comprising acasing and hollowcasting defining togethera'fluid passage, a manifold formingaclosureifor the heate'xchanger 'and'including means for introducing aheating medium into the hollow portion 'ofssaid casing in heat exchangerelation with the fluid and, alternatively,"

for by=passing the heating medium through the manifold when the fluidhas'been brought to pre-' determined temperature, means for directingthe 7, A heating system for fluids, comprisingthe combination withpumping instrumentalities for circulating the fluid, of meanscommunicating with a source of hot waste gases and adapted to pass thesaid gases in heat exchange relation with the fluid to be heated, a heatexchanger comprising a casing, a casting in the casing defining a fluidpassage between itself and the casing, a tubular valve within thecasting defining a gas passage between itself and casting andreciprocably movable within the casting for opening and closing the saidgas passage, and mechanism for operating the said valve including athermostat in contact with the fluid heated by the said gases andinstrumentalities operatively connecting the said thermostat andmechanism for effecting opening and closing of the valve responsively topredetermined amounts of temperature changes in the fluid whilepermitting continuous circulation of the fluid through the fluid passagein the heat exchanger independently of the operation of the valve.

8. Apparatus for reclaiming spent lubricating oils and the like,comprising the combination with a pump for circulating the spent oilfrom a suitable source theerof, of a heater operatively connected withthe pump adapted for the oil to circulate continuously therethrough,means for introducing a heating fluid into the heater in heat exchangerelation with the oil, means for returning heated oil to the pump forrecycling through the heater, and mechanism for controlling flow ofheating fluid responsively to predetermined temperature variations inthe oil, the said mechanism including a fluid-controlling valve for theheater, cooperating piston mechanism for actuating the said fluidcontrolling valve responsively to differences in pressure of thecirculating oil thereon, a master control valve for controlling the saidpressure, a solenoid for operating the said master control valve, acircuit for energizing the solenoid, and a thermostatic switch in thecircuit for automatically making and breaking the circuit through thesolenoid responsively to predetermined temperature variations in thecirculating oil for correspondingly actuating the fluid-controllingvalve.

9. A heater for fluid comprising a circuit including pump means and aheat exchanger, said heat exchanger being connected to a source of hotgases; shiftable valve means for deflecting said hot gases from saidheat exchanger; piston means operable by pressure of said fluid forcontrolling said valve means; and shiftable means for causing said fluidto exert pressure alternately against the opposite ends of said pistonmeans, and thereby to cause said valve means to shift and to deflectsaid hot gases from said heat exchanger.

10. A heater for fluid comprising a circuit including pump means and aheat exchanger, said heat exchanger being connected to a source of hotgases; shiftab-le valve means for deflecting said hot gases from saidheat exchanger; piston means operable by pressure of said fluid forcontrolling said valve means; and shiftable thermostatic control meansresponsive to temperature change in said fluid for causing said fluid tobypass said piston means, and thereby to cause said valve means to shiftand to deflect said hot gases from said heat exchanger.

11. A heater for fluid comprising a circuit including pump means and aheat exchanger; said heat exchanger being connected to a source of hotgases and comprising a casing and a hollow casting within said casingand defining therewith an annular space in the path of said fluid; valvemeans shiftable to direct said hot gases into said casting or deflectthe same therefrom; piston means operable by pressure of said fluid forcontrolling said valve means; and shiftable thermostatic control meansfor causing said fluid to by pass said piston means, and thereby tocause said valve means to shift and to deflect said hot gases from saidheat exchanger.

EBEN HUNTER CARRUTHERS.

